Miazza et al. (2025) Limits to the Estimation of Old Streamwater in Catchments Using Environmental Tracers

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Water Resources Research
• Year: 2025
• Date: 2025-11-01
• Authors: Raphaël Miazza, Paolo Benettin
• DOI: 10.1029/2025wr040718

Research Groups

Not explicitly mentioned in the abstract.

Short Summary

This paper introduces a framework to systematically assess the "critical age" in water transit time distributions (TTDs), which defines the maximum water age reliably identifiable by tracers. It demonstrates that the critical age is often significantly lower than previously assumed, typically below 1 year for stable isotopes and rarely exceeding 5–6 years for tritium in streamflow dominated by younger waters.

Objective

• To introduce and apply a framework for systematically assessing the "critical age" that separates the identifiable portion of a catchment's transit time distribution (TTD) from the unidentifiable portion, using different tracers.

Study Configuration

• Spatial Scale: Catchment scale (general).
• Temporal Scale: Water transit times ranging from months to several decades, with the study focusing on the reliability of identifying ages up to several years.

Methodology and Data

• Models used: A novel framework developed to systematically assess the "critical age" across a wide range of TTD shapes.
• Data sources: Tracer time series (water stable isotopes (O) and tritium (3H)) in precipitation and streamflow.

Main Results

• The critical age (the maximum age reliably identifiable by tracers) is often below 1 year for stable isotopes (O).
• The critical age rarely exceeds 5–6 years for tritium (3H) in streamflow dominated by younger waters.
• These critical age estimates are significantly lower than previously assumed in the literature.
• The findings advocate for the systematic evaluation of the critical age alongside TTD results to clarify which portion of the TTD is truly supported by tracer data.

Contributions

• Introduction of a novel framework for systematically assessing the "critical age" in transit time distributions (TTDs).
• Quantification of the limitations of stable isotopes (O) and tritium (3H) in reliably determining older water ages in streamflow.
• Challenging previous assumptions regarding the maximum identifiable water ages using these common tracers.
• Providing a method to enhance the reliability and interpretation of TTDs inferred from tracer data.

Funding

Not mentioned in the abstract.

Citation

@article{Miazza2025Limits,
  author = {Miazza, Raphaël and Benettin, Paolo},
  title = {Limits to the Estimation of Old Streamwater in Catchments Using Environmental Tracers},
  journal = {Water Resources Research},
  year = {2025},
  doi = {10.1029/2025wr040718},
  url = {https://doi.org/10.1029/2025wr040718}
}